skianduniaddict said:i did it differnet ly but i have a 129 in math and have verified it with
3 differnt sources here r the results
36"-1760
29"-2190
26"-2444
24"-2640
20"-3300
16"-4061
Without checking the rest, I can see that the first one is wrong.
You have used the diameter, not the circumference.
A mile is 1,760 yards.
A yard is 36 inches.
The circumference of a wheel is Pi x the diameter, or 2 x Pi x the
radius.
So, a 36 inch uni does Pi yards per revolution.
Counting Pi as 3.142
1760/Pi = 560 revolutions to the mile
To find the circumference of a wheel, take the diameter (20, 24, 26
etc.) and multiply by 3.142.
Now you have a circumference in inches. What is a mile in inches?
Simply, it is 1760 (yards in a mile) x 36 (inches in a yard)
1760 x 36 = 63,360
That means there are 63,360 inches in a mile. That's why old inch/mile
maps were in 1:63360 scale.
So, take 63360 inches (a mile) and divide by the circumference in
inches.
Taking the Coker again:
36 inch diameter x 3.142 = 113.112 inches circumference.
63360 / 113.112 = 560.15
The accuracy of your answer will depend on how many decimal places you
take for Pi. From memory, Pi = 3.1415926535 approx.
--
Mikefule
As each man has set up his loom, so will he endure the labour and the
fortune of it
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